1. Field of the Invention
This invention relates to hand-held, finger or mouth-actuated unit for permitting finger or mouth operation of a sewing machine by a person having a disability of the lower extremities. In particular, the invention relates to pneumatic control unit adapted to be connected to a controller for the electric motor of a sewing machine having a pneumatic input and an electrical output to the motor which is proportional to the pneumatic input.
Specifically, the invention concerns a small fluid bladder element having a nipple for receiving a fluid-conveying tube which is connected to the fluid inlet port of a conventional pneumatic/electrical controller operably coupled to the motor of a sewing machine. The bladder element is of a shape, size and material permitting a person having a disability of the lower extremities to control the speed of the motor of a sewing machine. Control may be accomplished by inserting the bladder element in their mouth and using the degree of closure of their teeth to control the extent of compression of the bladder element and thereby the pressure of the fluid on the input side of the sewing machine motor controller, which in turn regulates the speed of the motor.
The bladder element may also be used by the person by inserting the element between one or more of the last fingers of the user's hand and their palm, permitting selective finger compression of the bladder element, while at the same time leaving at least the thumb and first finger free to assist in guiding of material to the needle station of the machine.
2. Description of the Prior Art
Traditionally, sewing machines have been provided with an AC/DC induction motor for controlling the operation of the reciprocating needle and oscillation of the bobbin, as well as the coordinated movement of the material advancement unit. The controller operably connected to the sewing machine motor typically is of the combination pneumatic and electrical type, wherein pneumatic input to the controller results in a proportional electrical output to the motor. Increases in the pneumatic pressure to the controller thereby cause proportional increases of the speed of the motor and thereby corresponding increases in the speed of needle reciprocation, bobbin oscillation and material advancement.
Traditionally, the pneumatic/electrical controller for the induction motor of the sewing machine has been a foot control, knee paddles or a finger control on the housing of the sewing machine itself. The sewing machine motor pneumatic/electrical controller most usually has a closed bladder which is compressed or a diaphragm which is shifted by the foot control or the finger control on the machine housing. Compression of the bladder or movement of the diaphragm produces a pneumatic input from the controller and causes movement of a linear potentiometer, or a solid state pressure transducer to proportionally vary the speed of the induction motor.
However, if the user of the sewing machine has a disability of the lower extremities which prevents or limits the ability of that person to press a foot speed control, then the only option available was for that person to buy a machine with finger speed controls located on the sewing machine body. This meant though that the person necessarily lost the ability to use both hands in guiding the material through the advancement unit below the presser foot, significantly interfering with control of the fabric being sewn.
The foot speed controls that have been available are inherently too large to be held in a person's hand for operation of the motor of the sewing machine. Even if that was attempted, the individual still would not have both hands available for guiding the material beneath the presser foot.
Therefore, there has been a significant need for remote control unit that allows a person with a disability of the lower extremities to functionally control the operation of a sewing machine while leaving the essential fingers of both hands free to guide the material through the machine.